When connecting FotoStation to an Index Manager, a FotoWeb, or a Color Factory workflow, you will be asked to authenticate with a username and password. Typically you can use your network username and password, but ask your system administrator if you're unsure which credentials to use.
FotoStation stores the authentication information and reuses it the next to you access the same archive or workflow. However, it is possible to clear the locally stored credentials:
Open the File menu, choose Log out and select the server for which you want to clear the authentication credentials. Now, the next time you try to access this server you will be prompted to authenticate again.